The long-term objective of this study is to investigate ways of achieving good ocular alignment in children with congenital esotropia. Two clinical trials will be conducted. Trial 1 will evaluate Oculinum as a method of treatment for congenital esotropia with angles of 30-50 prism diopters. There will be two phases to Trial 1. The primary goals of Phase I are: 1. To estimate optimum dosage (number of units and number of injections) 2. To determine incidence, duration, and severity of adverse effects. Phase I of Trial 1 will study approximately 100 patients over a 2-year period. The purpose of Phase II will be to compare an optimal Oculinum dose schedule with surgery. The decision to launch Phase II of Trial 1, as well as the design and required sample size, will be conditional on the results of Phase I. Trial 2 will compare 2-muscle surgery with three/four-muscle surgery in patients with congenital esotropia > 50 prism diopters. Patients aged 6 months to 3 years will be randomized to undergo either two- or three/four- muscle surgery following specific surgical tables. For Trial 2, approximately 300 patients will be randomized over a 4-year period. The present proposal [to be carried out as a Cooperative Agreement by the Division of Biostatistics, University of Minnesota, the Department of Ophthalmology, University of Iowa; and participating clinical centers] relates to operation of a Data Coordinating Center for both trials. Responsibilities will include design of the study; development of protocol, forms, Manuals of Operation, and randomization schedules; training of personnel; randomization of patients; production of monitoring reports on patient accession, follow-up, adherence to protocol, endpoints, and adverse effects; tabulation and analysis of data for review by an external Data and Safety Monitoring Board; and participation in production of manuscripts and presentations on study results.